Polyethylene terephthalate (abbreviated as PET) fibers accounts for the main part of the polyester applied by the textile industry. The fibers are produced by e.g. poly-condensation of terephthalic acid and ethylene glycol, and drawing of fibers from a melt.
Polyester has certain key advantages including high strength, soft hand, stretch resistance, stain resistance, machine washability, wrinkle resistance and abrasion resistance. However, polyester is not so optimal in terms of its hydrophobicity, pilling, static, dyeability, inactive surface as a medium for adhering, i.e., softening or wettability enhancing compounds, lack of breathability and undesirable high shine or luster appearance.
Because of its strength, polyester fabrics and/or garments are subject to pill formation, and possibly the most important of the cloth finishing processes applied to polyester staple-fibre materials are those designed for control of pilling. All staple-fibre materials tend to form small balls or “pills” of entangled fibres at the cloth surface, when subjected to mild abrasion during wash and wear. If the fabric contains a substantial proportion of fibres having high resistance to flexural abrasion, the pills may be retained on the surface of the cloth in sufficient numbers to produce an unpleasant handle and appearance.
Another problem with polyester is that during synthesis of PET, cyclic or linear oligomers of poly (ethylene terephthalate), such as terephthalic acid-bis-2-benzoyloxy-ethylesther (abbreviated as BETEB) and/or cyclic tri(ethylene terephthalate) are formed. These oligomers are partly deposited on machinery and partly staying on and/or in the fibers. Oligomers tend to give fabrics a grayish appearance. This is due to deposits of oligomers on the surface of the fabric, which is particularly outspoken after high temperature wet processes like high temperature dyeing. The oligomers can be removed by severe alkaline treatment, which results in a significant loss of fiber material. Organic extraction of the oligomers is a technical possibility, but not industrially feasible.
The industry has made great efforts to improve the characteristics of polyester, in particular the reduction of pill formation.
WO 99/001604 discloses a method of reducing the pilling propensity of polyester fabrics and/or garments with a terephthalic acid diethyl ester hydrolytic enzyme (ETE hydrolytic enzyme) and/or an ethyleneglycol dibenzyl ester hydrolytic enzyme (BEB hydrolytic enzyme).
WO 2001/34899 discloses a method for modifying polyester comprising treating said polyester with a polyesterase enzyme.
WO 97/27237 discloses the enzymatic hydrolysis of cyclic oligomers of poly (ethylene terephthalate), which comprises subjecting the cyclic oligomer to the action of one or more carboxylic ester hydrolases.
WO 2001/092502 discloses the treatment of polyester textile with Humicola insolens cutinase variants.
However, there is still a need for improved benefit of enzymatic polyester fabric and/or garment treatment, including enhancing the efficiency of the enzymes to their substrates. In particular, there is a continuous need for more efficient enzyme composition to improve the economics of the process. The present invention aims to meet these needs.